No, that will only happen if they don't build commensurate units and do not charge the foreigners a good "foreigner price".
You're missing the part of the picture where a lot of Vietnamese get very rich (relative for VN) off the trend.
* Ingredient costs go up rapidly too.
* Because of that, the profit margins are narrow in the restaurant business at all restaurant price levels. There are rich restauranteurs here and there but owning a high end restaurant is still a very risky business venture and many are barely scraping by.
* You become talent bound. Finding chefs who can prepare food at that level is hard. Designing a good menu is very hard. Food is like any other creative art, you can't just arbitrarily decide to make amazing food—many try and fail.
* There is limited demand. Most people can't afford to eat high end food often and even those who can often don't want to go to the same restaurant over and over.
I don't see how any of this maps to the topic being discussed.
Capitalism, unlike what Marx claims,does not exploit. It co-opts. The locals always get their share. Some more than others perhaps but what can you do?